IVF Monitoring

What is IVF monitoring?

IVF monitoring consists of routine tests and procedures, including blood tests and ultrasounds, throughout an IVF cycle. Monitoring is a crucial part of the IVF process because it allows your doctor to know:

-If/when you are ready to begin an IVF stimulation
-What your hormone levels are throughout your IVF stimulation
-How your body is responding to the IVF medications (and if your dosages need to be adjusted)
-The size of your follicles as your stimulation progresses
-How close you are to ovulating

Without this knowledge, the following could occur:

-You receive the wrong dosage of medication and no follicles (eggs) grow
-You receive too much medication and run the risk of developing OHSS (more on this later)
-You ovulate prematurely and no eggs are able to be retrieved

During IVF stimulation, medications are given to hyper-stimulate the ovaries (so multiple follicles/eggs grow) and control when ovulation occurs.

IVF Baseline Monitoring

Your IVF cycle begins on the day you start your period. Keep in mind, though, that sometimes you may need to take medications, such as birth control pills or Lupron, before your period begins in order to prepare your body for your IVF cycle.

You should inform your IVF clinical team when your cycle begins. From there, your clinical team will schedule you for an appointment 2-3 days later for baseline testing. Baseline testing consists of:

  1. A transvaginal ultrasound of the pelvis, which shows how many antral follicles (follicles that have begun to grow) are in your ovaries. This ultrasound also checks for any large ovarian cysts and/or other abnormalities that may interfere with the IVF process, and it confirms that the uterine lining is thin (as it should be when menstruation occurs).
  2. Blood tests to confirm that you are not pregnant and to report your FSH, LH, and estrogen (E2) levels. These hormone levels should be low at this point in the menstrual cycle.

If everything looks good on your baseline testing, you will begin taking some of your IVF medications, which will hyper-stimulate your ovaries so multiple follicles (with eggs inside of them) grow. You will return 3-5 days later for your next monitoring appointment.

IVF Stimulation Monitoring

Another monitoring appointment is scheduled for 3-5 days after your baseline tests. This appointment will consist of:

  1. A transvaginal ultrasound of the pelvis, which shows the number and size of the follicles inside the ovaries (see picture). At this point, you should expect to see multiple follicles in each ovary that have grown in size since your baseline scan.
  2. A blood test that measures your FSH, E2, and LH levels.

If your hormone levels look appropriate and your follicles seem to be growing, you will begin taking a medication to prevent premature ovulation, and you will return to the clinic in 2-5 days for another monitoring appointment.

After 2-5 days, you will return to the clinic for:

  1. A transvaginal ultrasound of the pelvis, which shows the number and size of the follicles inside the ovaries. At this point, you should expect to see around the same number of follicles that were seen at your previous ultrasound (sometimes less since not all follicles respond to the medications), but they should be larger than they were at your previous ultrasound.
  2. A blood test that measures your FSH, E2, and LH levels.

The sizes of your follicles are measured in millimeters. Typically, follicles under ~16mm are too small to contain mature eggs, while follicles over ~23mm are too large (the eggs inside of them may be "too" mature). Follicles can grow ~1-3mm per day depending on how your body responds to the IVF medications, so the next few days may consist of daily trips to the IVF clinic for monitoring.

The dosage of your IVF medications may be altered to ensure that you have the best stimulation possible. Keep in mind that the quality of the eggs outweighs the number of eggs that are retrieved, so it is important to let them mature at the perfect pace.

Over the next few days, you will continue the same type of monitoring until two events occur:

  • 1. Some or all of your follicles are the "perfect size" (roughly 18-22mm).
  • 2. Your E2 level is really high (~200pg/mL per mature egg), your FSH level is still high, and your LH level is not high (we don't want the LH surge to occur yet).

At this point, you should be ready for your ovulation trigger. Administering this medication essentially causes an LH surge to occur, which then triggers ovulation to occur. This medication must be administered exactly when directed (typically 35-36 hours prior to your egg retrieval time), which should be right before ovulation will occur. If ovulation occurs before the egg retrieval, the eggs can become "lost" and unretrievable.

Common Questions About IVF Monitoring

Question 1: Can I have my IVF monitoring done at a different location than where my egg retrieval will be?

Answer: Yes. Outside monitoring, also called satellite monitoring, is possible. For patients who live far from the IVF clinic, outside monitoring provides the advantages of saving time and money. On the flip side, your provider must be able to see your results on the same day that your outside monitoring occurred, so they must be faxed/emailed/etc. ASAP so your stimulation is not delayed.

Question 2: What if I have a large cyst on my ovaries during my baseline scan?

Answer: A cyst is fluid-filled sac in (or on) the ovary that is "left over" from the previous menstrual cycle. The cyst can either be formed by the dominant follicle (ovulation did not occur and the follicle is enlarged), or from the corpus luteum (it was supposed to shrink after ovulation, but it didn't). Small cysts (<3cm) will usually resolve on their own and won't cause any issues in an IVF cycle. However, the presence of a large cyst (>3cm) can interfere with your IVF cycle, and your cycle may need to be canceled until the cyst resolves. If you have a cyst and your baseline E2 level is really high, your cycle will likely be canceled to give the cyst time to resolve. If the cyst is still present after a few months, it may need to be removed surgically (this isn't very common). If ovarian cysts are recurring, birth control pills may be prescribed to reduce the number of cysts that develop each menstrual cycle. These prevent a dominant follicle and corpus from developing, so cysts should not occur, either.

Question 3: Why did I originally have 10 follicles growing, but I only have 6 that are growing on the day of my trigger shot?

Answer: Naturally, multiple (antral) follicles will begin to grow at the very beginning of each menstrual cycle. These follicles should be visible on your baseline IVF ultrasound. However, as you begin to take your IVF medications, it's common to have some follicles that do not grow much or at all. Most likely, the eggs inside of these follicles did not respond to the IVF medications and therefore did not progress in development. Furthermore, the number of antral follicles is not always predictable (it's more of an estimate), so try not to focus too much on the antral follicle count (AFC) and focus more on the number of eggs that are actually retrieved.

Question 4: I had 10 "normal" sized follicles on the day of my trigger, so why were only 8 eggs retrieved?

Answer: It's not uncommon to have less eggs retrieved than expected. Some follicles may grow during an IVF stimulation, but these follicles may not all contain eggs (empty follicles). Thus, the follicular fluid may be aspirated (sucked up) during the egg retrieval, but there will be no egg inside the follicle (the eggs are too small to see on the ultrasound, so it's up to the embryologist to determine if an egg is present in the follicle). This is common in women with PCOS. It's also possible that some eggs stuck to the walls of their follicles during the egg retrieval. So, even though the follicular fluid was aspirated, the egg was not removed from the follicle along with the fluid. Finally, if ovulation occurs early, the egg may be released from the follicle before the egg retrieval. In this case, the follicular fluid is still aspirated, but the egg becomes "lost" and unable to be retrieved. Ovulation is timed for an egg retrieval, but some women still ovulate early even with the timed trigger shot.

Question 5: Why did I only get 3 eggs from my IVF cycle, but my friend got 20?

Answer: There are many fluctuations in the number of eggs that can be retrieved in an IVF cycle. Women who have a low ovarian reserve (low egg count) are less likely to have a large number of eggs that mature in an IVF cycle regardless of how much IVF medication they receive. Often, women over 40 tend to have a diminished ovarian reserve, which causes a lower oocyte yield during an egg retrieval. On the flip side, women with PCOS tend to have a higher number of eggs that are retrieved in an IVF cycle, though the quality of these eggs may not always be ideal. A blood test for your AMH (anti-Mullerian hormone) can help determine your ovarian reserve, which can give you an indication of how many eggs you can expect to have retrieved during your IVF cycle. Getting a low number of eggs can be disheartening, but keep in mind that it only takes one healthy embryo to make a baby at the end of the day.


IVF Monitoring - Medications - Ultrasound - Tennessee Fertility Center (nashvillefertility.com)

IVF | In-Vitro Fertilization at San Diego Fertility Center® (sdfertility.com)

IVF Cycle Monitoring – Fertility Treatment – Virginia Fertility Center Virginia Center for Reproductive Medicine (vcrmed.com)

The Baseline Ultrasound in IVF: What is It & Why Do You Need It - Alex Robles, MD (alexroblesmd.com)

Do All Follicles Have Eggs? Why You Got Fewer Eggs Than Expected - Alex Robles, MD (alexroblesmd.com)

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